The primary objectives of this proposal are to study the effects of experimental peritonitis on peritoneal neutrophils and to determine if there is a correlation between peritoneal neutrophil activity and survival of animals from peritonitis. Most of the previous studies related to neutrophil function and sepsis have focused upon the response of the blood neutrophil to bacterial infection. However, it has become apparent that the specific activity of peritoneal neutrophils is important in the host's response to intra-abdominal sepsis and, as yet, specific characterization of peritoneal neutrophil function during peritonitis has not yet been adequately studied. It is also apparent that an understanding of this mechanism is most important in an immunosuppressed host in whom the mortality from intra-abdominal sepsis is extremely high. In order to study the peritoneal neutrophil we have utilized a model of fibrinopurulent peritonitis in the rabbit and have developed a reliable method for harvesting cells and assay techniques to quantitate neutrophil chemotaxis, phagocytosis and microbicidal killing. With these methods now available we plan to direct our investigations towards A) demonstrating the stimulation or depression of neutrophil function by peritonitis B) utilizing chronic immunosuppression in vivo (using steroids, ethanol or azathioprine) to determine whether recovery and survival from peritonitis is depressed and if the effect on neutrophil activity is decreased C) using levamisole and zymosan immunostimulation to determine if recovery and survival are enhanced through an alteration of neutrophil activity D) determining if alcohol, cortisone, levamisole, zymosan, cyclic AMP and cyclic GMP have an in vitro effect on peritoneal neutrophils from immunostimulated, immunosuppressed or control animals E) determining if levamisole stimulation can reverse immunosuppression due to alcohol, prednisone or azathioprine.